Distribution of electric currents



(No Model.) 2 Sheets-Sheet 1. E. THOMSON.

DISTRIBUTION OF ELECTRIC GURRENTS.

No. 350,958. Patented Oct. 19, 1886.

WITNESSES: l/VVE/VTOI? ATTORNEY (No Model.) 2 Sheds-Sheet 2. E. THOMSON.

DISTRIBUTION OF ELECTRIC GURRENTS.

Patented Oct. 19, 1886.

fifflw WITNESSES:

ATTORNEY UNITED STATES PATENT OFFICE.

.FLIHU' THOMSON, OF LYNN, MASSAOHUSET DISTRiBUTlON OF ELECTRiC GURRENTS.

PECIFICATIGI-T forming part of Letters Patent No. 350,958, dated Gocober3.9, 1886. Application filed February 1, 1886. Serial No. 190,496. (Nomodel.)

To aZZ whom, it may concern:

Be it known that I, ELIHU Tuonsox, a citi zen ot' the United States, anda resident of Lynn, in the county of Essex and State of Massach usetts,have invented certain new and useful Improvements in the Distribution ofElectric Currents, of which the following is a specification.

My invention relates pz'u'ticularly to the con struction ofaswitching-magnet, designed more especially for use in electric-lightingsystems, as a means for controlling an elcctricswiteh, by the agency ofwhich circuits or connections may be automatically formed, so as topreserve the general circuit from rupture or disturbance of its normalresistance or continuity.

My invention relates to means whereby an artificial resistance may beintroduced in place o't'an incandescent lamp whenever the filament ofthe lamp is ruptured, or whenever too high a resistance exists in saidlamp, as, for instance, when through extended use the filament has losta part ofits conducting power.

So far as concerns the switclrmaguet itself, the invention is applicableto any electromagnet used in controlling a switch that affects thecircuit in or to which the magnet is connected.

The principal object is to prevent vibration ofthe inagnets armature,and to secure a steady action of the same, so as to render it insensibleto quick or sudden but momentary variations of exciting-current.

My invention comprises, also, certain other improvements in the detailsof the switchingmagnet and in the arrangement of circuits, resistances,translating devices, &c., that will be more particularly specified inthe claims, after having been described in connection with theaccompanying drawings.

I have herein illustrated my invention as applied to circuits upon whichincandescent lamps are employed, the invention being ap plied in suchway as to preserve the integrity or continuity of the line, so thatother lights or apparatus upon the same line may be practicallyunaffected in their brilliancy. I do not, however, limit myself to suchparticular application of my devices and combinations, inasmuch as theyare applicable to other translating devices besides incandescent lamps.

In the accompanying drawings I have shown in Figu re 1 theswitelling-magnet in longitudr nal section combined with an incandescentlamp and an artificial resistance, R, that is to be substituted for thelamp in case of rupture, or of abnormal resistance in the portion ofcircuit containing said lamp. The circuits over which current issupplied to the lamp and its adjuncts are indicated by the letters a I).

Fig. 2 illustrates diagrammatically the application of my invention toanother condition of working, to wit: one in which a number of circuitsfed from the same machine and in multiple arc to one another. Eachcontainsin series a number of incandescent lamps or other translatingdevices. It is to a system of this kind that my invention is especiallyapplicable, it being in such case especially desirable to keep theresistance of the several circuits constant and to keep each line closedat all times by substituting the resistance R for any incandescent lamp,in case the filament of the same breaks or otters too high a resistancefor practical work, or in the event of the lamp falling from its holderor not being inserted into the circuit.

Fig. 3 illustrates a modified form of my switchinganagnet combined witha group of incandescent lamps or other translz'iting devices, and with agroup of resistances individuallycqnal to an electric lamp andindividuallysubstituted therel'or in succession as the lamps or otherbranches are taken out of the general circuit by the agency of thearmatures for the said magnet. Fig. 4 is a side elevation of the magnetillustrated in Fig. 3. Fig. 5 shows a magnet combined with a switch thatopens the circuit to the lamp or other translating device at the sametime that it throws into circuit an artificial resistance the equivalentof the resistance presented in the lamp or other translating device whenthe same is in circuit.

The lamp L, Fig. 1, is placed in the circuit from (t to I) in theordinary way, said circuit being, if desired, one of a number ofbranches from a common source or from a common supply-conductor, orotherwise connected with a generator or an electric main. In a brancharound said lamp are the coils of a high-re sistance electromagnet, K,whose coils are wound upon a core, (J, of irou,which exerts anattractive effect upon its armaturcA, and upon. an increase 01' itsaction. to a predetermined amount raises said armature against thestress of its retractor, so that by making contact with aconducting-plate, D, the armature completes a branch circuit around thelamp through an artificial resistance, R, in obvious way. The armature Afor said magnet is pivoted in any suitable manner, and connection beingmade to it, asshown, said magnet-armature forms virtually an electricswitch. The armature is provided with a suitable retraetor such as aspring or weight, 'and normally rests against a stop, S. When thearmature is drawn up against the plate D, constituting the opposite stopi'or the same, the connection just men tioned is made through theresistance R. The resistance R is ordinarily equal to that of the lampL. Around the core 0, and at any distance therefrom, is arranged aclosed conducting circuit or band of copper or other good conductor, B,which is made of sufficient size to give considerable sluggishness ofaction.

to the magnet C by its effect in becoming the seat of induced currentswhich oppose any actions or changes of magnetism or movements of thearmature A. Thus should the current in the coil K increase an opposingcurrent will be produced in the band B, and should the current in Kdecrease a current will be produced in B to keep up the magnetism of thecore 0, or retard its loss. Similarly the approach or recession of thearmature Ais made deliberately or slowly by virtue of the same actionsin the band B, opposing any change of magnetic condition of the core 0,except through an interval of time. I find this action very useful incase of a switching-magnet used to operate switching mechanism, since itprevents undue sensitiveness to quick fluctuations of the currenttraversing the magnet unless the changes are fairly permanent, or maylast for some little interval, as a second or two, and the tendency ofthe armature to vibrate is in a great measure checked.

The adjustment of the armature A, or the power of the magnet K toattract said armature, is made such that when the lamp has its usual ornormal resistance the armature Awill remain down, and when thelamp L isout of circuit or has too high a resistance, the said armature, havingbeen attracted or drawn up, will remain attracted keeping in circuit theresistance It. This condition of adjustment is a very important one, andmay be expressed in another way. Assuming the magnet K to have a'normalpower, due to the presence of a proper resistance in the lamp L, thearmature A must be so adjusted that when away from the magnet it willremain away, and when put toward the magnet (the resistance It'at suchtime not being in circuit) the said armature shall still remain in itsattracted position. The results of such adjustment are that with thedevices arranged and connected as in Fig.1 a substitution of theresistance R will take place upon too high a resistance existing in thelamp L, or upon the rupture of its filament, or upon its removal fromthe circuit, or upon its failure to be introduced. On the introductionof the lamp L there would be two paths for the currentone through theresistance R and one through the lamp L. This willlower the potential atthe terminals of the magnet K, and there will result a falling away ofthe armature A and the removal of the resistance It- It is assumed thatthe current passing along the line is fairly constant. By this simplearrangement it is possible to operate with success a large number ofincandescent lamps in series and in multiple series from the samegenerating source, as indicated in Fig. 2, each lamp being provided withits switching-magnet, as I have described.

\Vhen it is desired to operate a group of magnets in each derivation ofthe circuit, and to provide a group of resistances which may besubstituted for the lamps on extinguish ment or removal from the circuitof the latter, I modify the arrangement, as shown in Fig. 8. Here themagnet has three armatures, A A A, although two or more may be employed,

and the core of the magnet, although it could be made as a single coreor piece, is preferably divided, so as to present a triple core, oracore presenting several poles, in accordance with the number ofarmatures used. The coil K is wound, as before, around thiscompound'eore. It is connected in derived circuit around the lamps, andit is of very high resistance, so as to avoid waste. Each armature A A Acloses a suitable contact, as in Fig. 1, when attracted, andtherebyintroducesaresistance, R, around or in derived circuit withthelamps LL, which are in a parallel group or in multiple are, as shown.The adjustment of the armatures is, as before, such that with a normalenergizing of the magnet K, and with the resistances R R Ropen-circuited, said armatures would remain either away from themagnet-cores or remain attracted in position that is, the increase ofmagnetic pull due to the approach of said armatures to the core wouldhold them near the cores, and on. pulling off the arma tures from thecores the consequent decrease would cause said 'armatures to remain awayunder the normal strength of the magnet K. The action or operation ofthe device is, with slight modification, substantially the same as thatof the apparatus shown in Fig. 1.

The whole number of lampsLL, or branches containing the same, is suchthat when circuit isclosed through them all in multiple are there is acombined resistance between the positive and negative supply conductorsor mains between which they are placedthat is, a normal resistance-andthat will cause a normal derivation of current through the coils of K.The arms or other retractors are so adj usted that under such conditionsthey will be against their back stops, and the circuits or branchesthrough the resistances It RR will be opened. These branches orresistances, as indicated, are each in multiple arc with the branches ofthe lampsL L, &e. If, now, a filament of a lamp, L, be ruptured, or thecircuit through said lamp be broken by switching or otherwise, theresistance of the multiple-arc group is thereby heightened, so as toincrease the difference of potential and to cause more current to flowin the coils of magnet K and strengthen the same. One or more of thearmatures A A A are thereby attracted or drawn up, so as to closecontact on a plate or stop, D, connected with a resistance, R, thusputting said .resistance into a circuit which is a branch circuit theequivalent of the branch circuit that it supplants. The current in allthe branches is thus restored to normal, and the power of the magnetwhose armature is drawn up is therefore now the same as it was beforethe action took place. The armature retains its position, however,because it is now nearer the pole of the magnet and is more stronglyacted upon. If two armatures are attracted, one of them will fall away,and so remain until a second lamp is cut oil, and a third action willensue upon a third lamp being cut off. The fact that one arn'iaturei'alls away while the other is retained is due to the circumstance thatit is impossible to so construct the magnets that the armatures willmove exactly together. The moment one'ol' them begins to move a littleahead of the other the magnet immediately begins to regain its power andwill act upon the more sluggish armature, retaining it in position,while the more quickly moving armature will have got beyond the powerofsaid magnet and will drop i'ullyaway. A number of resistances andarmatures equal to the lamps L L could be provided; but in practice Iiind that with a group of six to eight lamps a smaller numberot'resistances will amply provide .t'or possible extinctions by breakageor accident, it being understood that if all the lamps are to besuccessively switched an equivalent number of resistances should beprovided. The introduction of lamps into the group to replace those thathave been exhausted will cause a l'alling away of the armaturessuccessively,on aecountoi" the fall in resistance caused bysuchintroduction.

The arrangements that I have described are also useful. in cases wherethe current on the line a b fluctuates above and below a normal amount.Any increase will, as can be readily seen, tend to increasethe currentin the lamps in the group L L, to their injury or destruction, and atthe same time will more strongly energize the magnet K, the only resultof which, however, is to provoke said magnet to introduce successivelyresistances R R R in parallel with the lamps to preserve their normalbrilliancy and avoid trouble. A decrease of current will act in anopposite way to remove the resistances It and to cause the current tocirculate only in the lamps. The arrangement acts, therefore, in part asa regu lator, besides making the compensation which have been beforedescribed.

It is evident that the adjustments of the magnet K may be readily variedby loading its armatures, orin any other well-known ways,

to suit lamps requiring a higher or lower potential to operate them, andthat, consequently, in a system such as is exhibited in Fig. 2lamps ofquite different powers, due to their requiring different electro-motiveforces, may be introduced into the same system, since each lamp or groupof lamps and its arrangements becomes practically selfregulating on thecircuit.

In the switches shown in Figs. 1 and 2 the armature A is made to close acontact at D that will serve to introduce an artificial resistance inmultiple arc with a lamp or other translating device. It is sometimes,however, desirable to cause the switching not only to introduce theartifical resistance into a branch, but also to open the circuit to thelamp. Occasion for this extraswitching arises in those instances wherethe lamp may oll'er too high a resistance without absolutely rupturingthe circuit. Such a switching or opening of the circuit to the lamp maybe effected by means of a contactsuch as indicated at D, Fig. 5- throughwhich connection from the conductor a is completed to the lamp by simplyallowing the switch-lever, or a part connected therewith or with theconductor a, to make contact with the stop D when the armature A is inretracted position, or against its stop S. The closing of the contact atD takes place simultaneously with or a little before the opening of thecontact at D, connecting theline to the lamp. In this case it would beevident that the resistance It having been brought into circuit by theattraction of the armature A the introduction of a lamp at L of theproper resistance will not cause the opening of the contact D, sincesuch lamp remains permanently out of circuit, because of the contact Dremaining open. In this case, therefore, to re establish thelamp-circuit the armature A must be pulled off, at which time, if thelamp be of normal resistance, the armature A will remain unattracted andthe contact D will re main closed.

Vhat I claim as my invention is- 1. The combination,with anelectro-magnet, controlling switch-contacts connected to the circuit ofsaid magnet, of a closed conducting band or casing around the core ofthe magnet, whereby the sensitiveness of the same to quick impulses maybe retarded, and whereby also the tendency of the magnet to vibrate thecontacts automatically through the changes in the power of the magnetproduced by the opening or the closing of the contacts may be lessened.

2. An electric switch-controlling magnet having its armature andretractor therefor adjusted to permit the armature to remain in anattracted or an unattracted position with a normal strength of themagnet, and provided with a retarding band or conductor, B.

3. The combination, with an incandescent lamp or other translatingdevice, of a switch controlling magnet in derived circuit thereto, anartificial resistancein a branch around said lamp controlled by saidswitch, and a retard IIO ing conducting-band or conductor around themagnet.

4. The combination, with an incandescent lamp or other translatingdevice, of a derivedcircuit magnet and armature therefor adjusted toremain either in attracted or unattracted position when said magnet isnormally energized, an artificial resistance,R, in a normallyopen brancharound the lamp, a switch controlled by the magnet for throwing saidresistance into circuit upon increase of resistance in the lamp branch,and a closed conducting-band, of copper or other material,applied to themagnet for retardingthe action of thoswitchingappliances, as and for thepurpose described.

5. The co1nbination,with two or more translating devices, of a derivedcircuit around the same containing an electro magnet, two or moreelectric switches operated by said magnet, and resistances controlled bysaid switches and. placed, respectively, in normally open branchconnections around the several translating devices, as and for thepurpose described.

6. The comhination,with anelectro-magnet having a multiple core, ofarmatures for the several individual core portions, and switchescontrolled by said armatures, as and for the purpose described.

7 The combination of an electro magnet having several core portions andplaced in derived circuit to the portion of circuit containmg the work,two or more switches controlled by said electrc-magnet, and artificialresistances, one for each switch, said resistances being innormally-open branches around the portion of circuit containing theworking-resistances, as and for the purpose described.

8. The combination, with a group of incandescent lamps or othertranslating devices arranged in multiple arc, of an electro-magnet in aderived circuit of high resistance around said group, and provided withtwo or more armatures and artificial resistances in separatenormally-open branches around-the group of lamps or other translatingdevices.

9. The combination, with an incandescent lamp, of twoelectro-magnetically-controlled switches, a circuit to the lamp governedby one of said switches,and a branch circuit controlled by the otherswitch and closed simultaneously with the opening of the circuit to thelamp, as and for the purpose described.

10. The combination, with an incandescent electric lamp, of anelectro-magnet in a derived circuit thereto, two sets of switch-contactscontrolled thereby,'a branch or circuit leading to the lamp and normallyclosed by one ofsaid sets, and a normally-open branch around the lampcontaining an artificial resistance and controlled by the other of saidsets.

Signed at Lynn, in the county of Essex and State of Massachusetts, this27th day of J anuary, A. D. 1886.

ELIHU THOMSON.

\Vitnesses:

M. L. THOMSON, J. \V. GIBBONEY.

